Varnish安装

cat << EOF >> /etc/yum.repos.d/varnish.repo
[varnish]
name=Varnish for Enterprise Linux 6
baseurl=https://repo.varnish-cache.org/redhat/varnish-4.0/el6/
enabled=1
gpgkey=https://repo.varnish-cache.org/GPG-key.txt
gpgcheck=1
EOF

yum install -y varnish

Configure Varnish

There are two configuration files to edit, /etc/sysconfig/varnish and /etc/varnish/default.vcl.

Assuming you want Varnish to run on port 80, open /etc/sysconfig/varnish and change VARNISH_LISTEN_PORT to the following:

VARNISH_LISTEN_PORT=80

Next, open /etc/varnish/default.vcl and
use the following configuration. Be sure to replace PUBLIC_IP_ADDRESS with
the IP address of your web servers.

vcl 4.0;

import directors;

backend web1 {
.host = "PUBLIC_IP_ADDRESS";
.port = "80";
.probe = {
.url = "/";
.interval = 5s;
.timeout = 1s;
.window = 5;
.threshold = 3;
}
}

backend web2 {
.host = "PUBLIC_IP_ADDRESS";
.port = "80";
.probe = {
.url = "/";
.interval = 5s;
.timeout = 1s;
.window = 5;
.threshold = 3;
}
}

sub vcl_init {
new apache = directors.round_robin();
apache.add_backend(web1);
apache.add_backend(web2);
}

sub vcl_recv {
set req.backend_hint = apache.backend();

unset req.http.Cookie;

# Do not cache listed file extensions
if (req.url ~ "\.(zip|sql|tar|gz|tgz|bzip2|bz2|mp3|mp4|m4a|flv|ogg|swf|aiff|exe|dmg|iso|box|qcow2)") {
set req.http.X-Cacheable = "NO:nocache file";
return (pass);
}
}

sub vcl_backend_response {
# Set cached objects to expire after 1 hour instead of the default 120 seconds.
set beresp.ttl = 1h;
}

sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
}

Enable and Start the varnish Service

Enable the varnish service
on boot:

chkconfig varnish on

Finally, start the varnish service:

service varnish start

Verify Varnish is Working

Assuming everything is working properly, and have changed your website’s DNS entries to point to the new Varnish server, you should be able to browse to any of your websites in a web browser without issue.

If you have not yet changed your website’s DNS entries to point to the new Varnish server, you can still verify Varnish is working by running command 

curl
-i -H 'Host: example.com' varnish.example.com | less

 (example.com is your website’s domain name and varnish.example.com is the hostname of the new Varnish server). At the top
of the output should be a header called X-Cache. The value of this header will probably be MISS. If you run the curl command again, the value should now beHIT because
Varnish cached the web page after you ran the first curl command.

Once you change your website’s DNS entries to point to the new Varnish server, you can run a similar curl command,

curl
-i http://example.com | less

, to verify Varnish is working.

In addition, you can monitor what Varnish is doing by running 

varnishlog

, 

varnishhist

, 

varnishstat

,
and 

varnishtop

 on the server running the varnish service.

Troubleshooting

If you have problems starting the varnish service, you will find there isn’t much information to troubleshoot with. I ran into a situation where 

service
varnish start

 simply failed with no debug output.

Output from /var/log/messages only showed No VCL available. In addition, running 

varnishd
-d

 also only showed No VCL available. Not very useful.

Luckily, you can get much more useful debugging information by running 

varnishd
-C -f /etc/varnish/default.vcl

. This actually told me where my syntax error was.
安装后服务不能启动解决办法：

关闭防火墙chkconfig iptables off，关闭SElinux: vi /etc/selinux/config 将SELINUX=enforcing改为SELINUX=disabled

curl -i -H 'Host: 192.168.3.66' 192.168.3.59 | less